Answer: d) 
and 
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
A neutralization reaction is a double displacement reaction in which an acid reacts with base to produce salt and water. The 
ions from water reacts with 
ions from base to give water.
Thus products that will be released when the antacid is mixed with the hydrochloric acid in the stomach are and
Mutualism- both organisms benefit
Commensalism- one organism benefits while the other neither is harmed or helped
Parasitism- one organism is benefited while the other is harmed
4 P (flea benefits but dog is harmed)
5 M (both get to eat the honey)
6 C (bird gets a place to live without harming or helping the tree)
7 P (lice get a place to live but humans are harmed)
8 M (both are helped)
9 C (flower isn’t harmed or helped but bee is helped)
10 P (the tree is harmed but the mistletoe is benefitted)
Answer:
The calculated concentration of sodium thiosulphate solution will be less than the actual value.
Explanation:
When IO3^2- solution is added to KI solution, I2 gas is released ,then sulphuric acid is now added to facilitate reduction. In order to prevent the escape of iodine (I2) gas ,the solution must immediately be titrated with thiosulphate.
If the solution is not immediately titrated with thiosulphate, the concentration of iodine available in the system decreases. When this occurs, it will also cause a decrease in the amount of iodine available to react with thiosulphate thus decreasing the concentration of thiosulphate obtained from calculation
It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms.
These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.
